CAT 3G-1681 RETAINER

CAT 3G-1681 is a commonly used spring-loaded shaft end retainer (cotter pin + spring clip integrated type) for Caterpillar construction machinery. It is suitable for hinged parts such as pins, connecting rods, and bushings in mini excavators and loaders, used for anti-loosening positioning and axial limiting. The following is precise technical and application information:

Core Technical Parameters
Item Details
Part Model: CAT 3G-1681 (3G1681) Shaft End Retainer, weight approx. 0.045 kg (0.10 lb), suitable for pin diameters of 18-22 mm

Core Materials: Body (65Mn spring steel, wire diameter 4 mm, hardness HRC 42-48, galvanized passivated surface, corrosion resistance ≥480 h neutral salt spray); Clip (60Si2Mn spring steel, wire diameter 3 mm, elastic deformation ≤5 mm); Cotter Pin (304 stainless steel, diameter 3 mm, length 25 mm)

Key Dimensions: Opening Width 12 mm, closing width 8 mm, total length 65 mm, snap-fit ​​inner diameter 19 mm, compatible pin groove width 4 mm, groove depth 2 mm, cotter pin hole diameter 3.2 mm, chamfer at both ends 0.5×45°

Rated parameters: Operating temperature -40℃ to +150℃, rated axial positioning force 8 kN, compatible swing frequency ≤10 times/minute, ultimate tensile strength 15 mm, compatible pin hardness HRC 40-45

Suitable working conditions: Axial positioning of pins under medium to low loads and frequent swinging, suitable for vibration and impact conditions, anti-loosening and anti-falling, compatible with NLGI 2 lithium-based grease

Compatible models: CAT 303CR/304CR mini excavator (stick – boom, linkage – bucket), 903C loader (rocker arm – pin), 216B3 skid steer loader (working device articulated)

Accessories: Compatible pin 175-4037, Bushing 5G-0811, Bolt 106-7772 (M12×20), Grease Nipple 1U-8878 Core Functions and Structural Features:

Anti-loosening Positioning: Double anti-loosening mechanism with spring clips and cotter pins counteracts loosening caused by vibration, suitable for frequent start-stop and impact conditions, ensuring axial fixation of the pin.

Quick Installation and Removal: Elastic opening and closing clips allow for installation and disassembly without special tools, suitable for quick on-site maintenance, improving work efficiency.

Wear and Corrosion Resistance: Galvanized passivated spring steel surface and stainless steel cotter pins, suitable for dusty and humid conditions, extending service life.

Precise Fit: The inner diameter of the clip precisely matches the pin groove, with no radial clearance after positioning, preventing pin wobble and wear.

Safety Redundancy: Dual fixing structure allows for temporary fixation even if a single component fails, reducing operational risks.

Installation and Maintenance Points

Installation Specifications: Clean the retainer, pin groove, and mounting holes, removing burrs and oil stains. Check for cracks in the spring, deformation of the clips, and rust on the cotter pin.

Snap the clips into the pin groove, and insert the cotter pin into the retainer and pin hole, with a bend angle ≥90°, ensuring a tight fit between the clip and pin without gaps.

After installation, test run. There should be no jamming or abnormal noise, and axial movement should be ≤0.1 mm.

Maintenance Recommendations: Check the retainer’s condition every 200 working hours. Replace the clips immediately if they become loose or the cotter pin is deformed.

Avoid prolonged overload tension to prevent spring fatigue failure. Clean regularly and apply lithium-based grease to prevent rust.